New surgical approaches are now being tested for use in kidney cancer. For example, some doctors at major medical centers are testing laparoscopic approaches (using long, thin instruments inserted into the body through small openings) to remove only part of a kidney (partial nephrectomy).
Other, newer approaches to destroying small kidney tumors are also being studied, especially for people who are too sick to have surgery:
• Cryosurgery uses a thin probe that is inserted into a tumor and cooled to very low temperatures to create an ice ball to kill the cancer cells. It is probably the most widely used of these techniques at this time.
• Radiofrequency ablation involves inserting a metal probe into a tumor and passing an electrical current through it to heat up and destroy the tumor.
• High-intensity focused ultrasound is a fairly new technique that is now being studied for use in kidney cancer. It involves pointing very focused ultrasound beams from outside the body to destroy the tumor.
Research is now under way to determine how useful these techniques are in the long term and to refine them further.
Targeted therapies
Because chemotherapy drugs have not been very effective against advanced kidney cancer, targeted therapies are now usually the first-line option to treat kidney cancers that cannot be removed by surgery. At this time they are usually given separately. Clinical trials are now under way to try to determine if combining these drugs, either with each other or with other types of treatment, might be better than using them alone. Several new targeted therapies are now being tested as well such as the tyrosine kinase inhibitors axitinib, pazopanib, and the mTOR inhibitor RAD001.
The potential roles of adjuvant and neoadjuvant therapy are also being studied..
Immunotherapy
Kidney cancer is one of a handful of cancers that may respond to immunotherapy. Clinical trials of new immunotherapy methods are being tested. Basic research is now being directed toward a better understanding of the immune system, how to activate it, and how it reacts to cancer.
Researchers are studying the use of cytokines to stimulate immune system cells that have been removed from circulating blood. After being mixed with the cytokines in the lab, the activated immune system cells are then injected back into the bloodstream. The hope is that the stimulated immune cells will then seek out and attack the cancer cells.
Some researchers have taken this approach further by identifying special immune system cells called tumor-infiltrating lymphocytes (TILs) that can be found within kidney tumors. These cells can be isolated in the tumor after surgery. Researchers are looking to stimulate these immune cells by exposing them to cytokines in the lab and then returning them to the body in the hope that they will attack the cancer cells.
Vaccines
Several types of vaccines for boosting the body's immune response to kidney cancer cells are being tested in clinical trials. Unlike vaccines against infections like measles or mumps, these vaccines are designed to help treat, not prevent, kidney cancer. One possible advantage of these types of treatments is that they seem to have very limited side effects.
There are several ways to create vaccines that might stimulate the immune system. In one approach, cancer cells (removed during surgery) are altered in the lab to make them more likely to cause an immune response and are then returned to the body. In another approach, a special virus is altered so it is no longer infectious, but it carries a gene for a protein often
found on cancer cells. Once the virus is injected into the body, the hope is that the protein will cause the immune system to react against cancer cells anywhere in the body. Combining vaccines with targeted agents or other agents to help them work better is also being studied. At this time, these vaccines are only available in clinical trials.
Bone marrow or peripheral blood stem cell transplant
In people with advanced kidney cancer, the person's own immune system is not effectively controlling the cancer. Another approach to immunotherapy is to try to use someone else's immune system to attack the cancer cells.
First, very primitive immune system cells (called stem cells) are collected from a compatible donor, either from their bone marrow or their blood. The person with cancer is then treated with chemotherapy drugs, either in lower doses (called a mini or nonmyeloablative stem cell transplant) to suppress the immune system or in higher doses to cause more severe damage to the immune cells and other components of the bone marrow. They are then given the stem cells to try to build a new immune system that will be more likely to attack the cancer cells. Some early studies of this technique have been promising, finding that it may help shrink kidney cancers in some people. But it can also cause major complications, and side effects can be severe. Until more is known about its safety and usefulness, it will probably only be available in clinical trials.